SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9737a728825e77d1c832000b554534953b34a1bd6c9527370091f0d69f9a5bf4' 
  AND token = 'yQGGnFPph/WLpWPyZzUzrAiHyiF2uZKEnNQ4Xc+Dav0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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