SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a39b60fb7c571da1c73b5999110ab1a42627844fc5d3b0fdda1e7f4e9020e826' 
  AND token = 'DOsDmIDfNR7WTem51pB/RpgK+AjDKAmboKnRIztXlLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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