SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dec1972e30252977db31cae0e871bef5e4a80dbb2e9efcd4bd926ed4a2f320cc' 
  AND token = 'i0ohPhQcYSXuod6hIpLKT+QlIdAoVpqAdf59rBkCMe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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