SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7492e098b9d5004be30dd71952c79720fcae57a01aa63e76495b13a08422b232' 
  AND token = '8p5yZJJ41bDlC3fbKNpTMtMHnXqwSTohnMN5IOrqQhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}