SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '478df00aad6e53e397f2e4d2ca6b89172f21c3e4627488bcc750d7eba3b217f5' 
  AND token = 'P6hINgzbg0b3U7YFDkN2upBHy0p/kbGxbBlU56OgMrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}