SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '699302c8c918a9a249e16284715914eaeecf152f387f135b4a6818dccacdb883' 
  AND token = 'wricDugW3K924Laj0HlEKtaJri3ZQEEWnd4tnJI9Hyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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