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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '478314710ea8c147d2f0d7f5caaacdbe012d304761142e2aa563a8c3ef565ccf' 
  AND token = 'fbRs0XaZtmTQv4Kv9s4Gc7uXNFbm1n5/klNufBtV3Z4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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