SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f70fe5f2fc0e75f5866159e71fa04ad3f7e8fe4fba307ff880fd86ea82a4e898' 
  AND token = 'sF16mTWA8T2N/zIPt1gjZGggsjHXK3OoWIUbofBy8Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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