SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2c0978299d33fb3df21c536d0c83a57fef635cdd2d24c2be689d3e973c16eb2' 
  AND token = '0j+BpCvnoQ1qrWukTGdhYhvs9W01JoaPOVvFXHltJt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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