SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '980602eaacebe6439a97f5a5b37527b57fd3b01532582f48bb768d63b5ae4c43' 
  AND token = 'UtNK6fGVeZQEnhz6NzkeWBliq4lt8dcFDSutJGWigS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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