SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c33b870c47771155c391e402edae2a6899cbc9f63e69128ab5d9637e2b55805' 
  AND token = 'k6vavSztR0273+Xqt7EIH3s4dhdeMAXkdNfLdvBja0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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