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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5483e15693b23f5151abc36709e7eba0e5a59aa3186ccdd1d0f24506a80083b' 
  AND token = 'qjaT02ywAs5t1RuYrW/THeL5brD7IxmDukzqERUuQxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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