SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ee2faa16207185fd67a6568d6a229b34fb551af20171005e8776c1c1e3ff2a10' 
  AND token = 'MY+NvKw+3I30gfXOMkGze5XjlenHYx+jaOnevM6rz2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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