SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '372e251bda83616b4f80d310390cc2dffe3319eb9e9881f034077d059c2a9119' 
  AND token = 'kH1YUUgXnQ4ZT7ZNTwc0OQApVGEVkVGY4K7E0USslGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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