SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69abec451e56490bf2ed86969b93fca899e7815e85683cfc1cceb2432cad3507' 
  AND token = 'xIMn82ujjkfsUzhYG2OIaUEPCAMgGrd5K04Vc+k9WIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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