SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61ffaf6fe2e0476005c2fb51b45d17d6dcb54b89e3dcfd81643a8c0708fe8b5e' 
  AND token = 'zIHukJtCh5uPnuD7LLrRxBwhmARApUPqv4lwQmc6WwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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