SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '884a1f7262c542c7c50351da19cdf5827bca2c78cee08ec47f7dd0901eaa5a46' 
  AND token = 'e5t4oInDXI8zM6lgnAs5FgFtIkXSRQba4XBZuxfHHqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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