SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4df46e551a06e8ba62fe6c7a79e343581938a266f9c420d5d34500e6f4035b07' 
  AND token = '/DrYNPzjLWh8wLSZfy1Twyj9wAxHP8GB+HoBcRFDmYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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