SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a531b5d44bd3bd7925ba32d4d98c93a0a2ba138dba8ad13750c2a251a04d1475' 
  AND token = 'YPvt2Fc9U1IXhF6c2WJV9Gn4MupNCCIlBW7xiA8BQd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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