SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7628e2fe0a2eabfd680619cfc892ca276ac43add98cbed2529511df628a684e1' 
  AND token = 'bjiauL/n9atZk1hBZPUoFuedVCCjROnVFjOFkZ08J0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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