SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dc7865242aa478c7bf0e95619b519e86b48898f7e19348b3c778d428a6e1f3a' 
  AND token = 'dDVl4QGQI+KaYW/OdAgfwSVXkVBu85XQFUqdh5ev5hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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