SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8529573d86796a91232396446948cbb1dcc29d2dbe071c3ff0475cbd2010ecd5' 
  AND token = 'QquWbrfkMxKbu9ES+rqtEdq57zihYzMo03VPkfxUNu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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