SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef831a0b3b507f819b5f13794c1b4d698028486b005de83073c4a7a8483665b9' 
  AND token = 'dZR/gRuUJklF+OQdYccvnw3ku8/oGHj2pRbh/H4yXOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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