SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b524ad99c62593bac5b78a931be8781ccd7b45b4da610039e60f11945fab6bf3' 
  AND token = 'nmjyRfYxBXSvWP11PVCSOOkWrWQX0C6/y5Pu6tKnXAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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