SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6bdad04f1517f6070369bc76b4093cb7d63224f5eb5f8b293966a1fd6fc0938' 
  AND token = 'bhMMekftzUGiTYbY+CT6WYpLVuuDCNVe1V2urTMVaGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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