SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61f9aaab6f060ffef315df0e44c111b7839660d5907c2d5e821d990e074013fc' 
  AND token = 'U2KQOrWZF9K0d1PTEhOHGBnRCjtaCg/fuhrLLFfeJH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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