SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02f8616186767af7952f9ef641873e530f465183e9bfb3dc252aff9845a9a8ed' 
  AND token = 'OSNL7f4CAIu+zgpREQ82057YwnIDGYzOVJQyp5qB4k8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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