SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e858231b2783631c596ab0d67e2d897fe5b417e423c0d75397d74000dd90f3ef' 
  AND token = '+fJTXflLfPJ/yGLvlfgq9yLIFzg0GY/GwtRfYZ9L8wM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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