SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4aa59e34ff99984b25ef1480e768cb211c3e3920707cfe759d46c7b84529512' 
  AND token = 'Nso9hQctYV3jlxL/WzgyKdro6+dpLazOJyXFtHb/M6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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