SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '016e56f298baa2409ec15427bc8559fb41c097d2999873da073bed81a0493fce' 
  AND token = 'Y3s6y0uxH2qk2PSUj7aH6ov2IoR7qobIcKYQnDJUJ0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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