SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59b12fb717e180e1ca0224542be4ea5e60b3d3d0c58fbd03d2816163f6d559c9' 
  AND token = 'YxIEwUUIRYEaFZqlgIy6quFEuuyYiTa+5ttBUKBZSuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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