SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e0fdceb14094bdeb999e6be622474259f71b1fea855c79cd475a271b87fcd34' 
  AND token = '7ezPerKghWKM9UZhYW2Y+yEu0MLZmLHPmVYGlHQUzOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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