SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '427476da52eb9856d8d2c2f5c37504e7a8bb5195581c989e60ac519f4dee927f' 
  AND token = 'ZefxvbosBDvEK5toy74okMVx37mqLX8GsC9IEDx9byo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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