SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe62722d36f61790666b9ad725cb3ea9c15a066e99671855fe9ef05259d2ff49' 
  AND token = '6IPVkSreIs6zuZarAcPIvwT1Q8RS31o8ktZ5bUXkNM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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