SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '40d48df52b8b3c93e5b562a28dd9a8a5174a1ced5c65c9e6aab3fac4bbbcf4dd' 
  AND token = 'HE/CD37XSKodrJ6mMQgPDZdaRiR6Cwzj1Cw2fYD+GS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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