SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c910e91ea9b405f3010047ce846eb5ce4a66051b1dfb71bd82b6230e331e600' 
  AND token = 'cHwlQ7i9TkgSi5nbCkOYwf6xfH+bxKplVLDCMPvZVUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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