SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '88dcbd6144d18f098a23a896358c12b729297374dba54dccae6e34aaabbb1253' 
  AND token = 'S9m4MW2yzsnB9+oP5tLFhq/6qzzRbGA9dxhpWzZEs/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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