SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a319d01358e17e936b9079a9507705f5ae79225af793c59bfaa6479e4dac481' 
  AND token = 'orU+OHhbeHtNJAtECKQJqj+Imuu6OQ9DgJSx3018UJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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