SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '242324530fa0214aca20b33f9f9d72712b7e3ce339735d618fce8f7e6c5f6760' 
  AND token = 'fPXGHxaYWvF6/zGEHc+nE6Lqs3KPeAp2dxjXXg8SRug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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