SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1891505c39600c125979471cb5a24a0868b8e9630220f570a2ae192449d0c164' 
  AND token = 'Z4Q/VD+KK5spOfYtEghCpu/QPC9v3eKLfG+cvEty8qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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