SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab1ad647f373adcae9d9f2e45e000b42553c39af62807171b1953438e63d6952' 
  AND token = 'HCzmDdc14BywFaLuRKQ0WMdBRqnoLolszp5ghrw0oqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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