SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac75836b5b1917fca1d0eb7d78db4dff0f6cb669b31a1878a452664caa669818' 
  AND token = 'NYye7xKJyR4EtsT3eLSIOj8jrwdU5YnAVz4z88IUzJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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