SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f0bd83fef387e0800793b997f8df18bef8b134c26c3052a4a712ecdc070a467' 
  AND token = 'uIaOhUX1CMAqhNJtDuodGjFKdXgwietsktxwkwleA0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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