SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e6ae6d8aa2cd27122df55e246bf9636d2e869068546e4214283614967215c17' 
  AND token = 'R6r9v6rUZjW1bqgnC9CvBIaIRbSpOnbj/6bJt6OeNYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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