SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e1d5d574ba2e49df4a30dbdb05e46c7e697bec1bb60c012a923eea4f5c30518' 
  AND token = 'qzZ3x+bUAxsFsUVWWfKGtWlVZVrQwGJbVWFIuARK2xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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