SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28c48740214f2398c232291959d6b4b7aa30d9f8a33d3c645966d9be96b5579e' 
  AND token = 'qP+ExwI/BsSsJhktWK8qwQquf2FiJs49LJ2qlyXqHeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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