SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7451f86355239d38329597e76d4601a27b0ccfc1735449414f5d327a2d2725b0' 
  AND token = 'YPbrd8paIFOuLsY21oIMVKvv6H3MAblXuDicM/bDtuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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