SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa6968ac9000737a8818cef732a607091f27a8a08e0e9b8e6ddcbafbca969f88' 
  AND token = 'qoONs7UbuAzj5t9gHd7HLQsMVnGiYkxMdi6PFL66INQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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