SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '87a1df6741504f859dcc40f4fce41fadafb48fe906582ebd9a0d199bba4189bc' 
  AND token = 'O5VZy39hT+iXbrhz06oetAx2Nou+S6gIPYeRcGT+/3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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