SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54839ea865a78ac92a554d4905d4e2d4eb1a657500e2bf1e44ea811cb66cc9a9' 
  AND token = 'B4yBpEfJ0gvqYPbbNcerRmzxonpqwiLmfpYvJUJaGhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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