SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db28d5133b5e3fb5709511c127fb2d082abffbe378144003f67ba686babbc36a' 
  AND token = 'PzcKJZ0hRUxXqT81Mc/ng0KoyzvGtOpRRtX7S+0jz0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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