SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '551a9c56447691a284eb33781b2f1bad87554e9a20e4b83219f680175f135f43' 
  AND token = 'egENHhVT6V6jVu/ZCSEV1fIpKyRqK5SLRg/ounNbfbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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