SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f92a31ea3dfd31a8ac8f8d327e1e597b390182ca427ff59e08a70d45d74e3494' 
  AND token = 'Qxi+FYysFJoXqcNhkTNxALm/EsJyKYZ6q+nBL0yh7Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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