SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3904be1849c07cdec1d3fb4f19de947e1e38d94690ebf2e1ea8af270cdbc556a' 
  AND token = 'KsbpSchA6DoxLaRNUgzeAShfI9nSV6iHRdb7z/p31CA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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