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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a78bea38b827d54c6c294f69d235cc783da12dfd50a9b96c520012c9146f4607' 
  AND token = 'QjrSAmQXbxadLnYW1TKGEygLhM+Orbcc2UhSGJz2QDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}