SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '42ad648b6bb981064f611f0dffa163f2ab763a61044dd93434791b340e2499fe' 
  AND token = 'pynCFwKabSiMzbIpEXQBW6nZAm/YG+KRQ8E7Li5fB/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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