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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9011a7d0a41dea567df717e151a231b272630abf37eb8b643d9613a3a83fb9b4' 
  AND token = 'dPvxa3f2kn3L2O8TUSDoNFKAnDi8DFz997LEZHMjflQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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