SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93d9ec4884669b78c6fa97d054a188d549e99b844b8cc8cc8dfb113b4da11286' 
  AND token = '4vRJLdgxfDY8xxlPmdJiRwsV8EDQP3sj6e3wnFAJsXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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