SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2acc47c8e7cac479a4e1929c4ec85b2761393aa174ae2bc8704ca013db4c0454' 
  AND token = 'qVXlG19wHP9nqhBsLPwlhOyGFC9zzjPmHHBYwlnKeYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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