SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b4aa95db96aafb29cdf8123f44437731700453d8c2055429303b2bafd35dcfd' 
  AND token = 'WjCExrHdKmwdhoQbZ7UKY5zNe9krsL6WPNJs4bt/IQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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