SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1d1e18920dcd5a8e7327e52146dd7bb36d84be2429352bc7019624f8ab98c82' 
  AND token = 'iueXIZnJ5NhEc3shJjMOWSLnScatajaQLz+MUh0tH40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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