SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a69cee6c2017a69d46f472c7fdfab3ae2e915ed8a51aaf2c688eecefd3114ca1' 
  AND token = 'nuy4FT/3lQFHMWsXqioNEKuI+fIdLcL9pnfhPVLL81c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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