SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb52b04fde2fdb348bc4d285795248cb3f58d4754b63f710d63ff87a3e53994e' 
  AND token = 'sybTXLZHy/oqyyI0PdKnwKMjOO2fh+ri/7cOG9mN4aE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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