SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dceecf91cec69664a002bbcbe3d85446a499a0d210717751ea94394213cfe8ff' 
  AND token = 'ISMbaKItkTbGxsZecG+wju0dGtOj987wKvv9+X7ro2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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