SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '278f2a3177b7b9e881efc3b09ef9c57bf1152527a87619241089850778eafb94' 
  AND token = '0TG8SncrfPQtZek6yRRuv3V/K1t4TznJyTyFel8AwHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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