SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fe78b5fa33460c0fc942eaf45bee9e82279c09727729a170503b38af904b023' 
  AND token = 'IC86ue0kgSAxFavAxZ7lYiAZOV1tejo+/nqeT7+AKCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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