SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a57994e18b663de00383219684c04e73a2f21558c4e27aad3f6266dc8bec7014' 
  AND token = 'CVKR89CKJiYqfjzVjYCX2F21tdkUqJiRLcWkAvFsRKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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