SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f7a39720abeacfd4bed5d769c0809133067d621d2f82879c5041b9539600b296' 
  AND token = 'TpQqYTxtg9/zliTJ4smP+Dh8Xqzb6joZC8q8ImG/qI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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