SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57b5fdf2c70aa823aee03dc73163ad62d733ed21624a906173e935b316377e04' 
  AND token = 'YQWnBjQEZ2D1A/ZGfH5uQueXxEgd3yM+oDbl2pYPBeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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