SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '991cd08102db899df42a12758a96ecfd9ac1e5fcce5e68d5d0fce5f91028f0e2' 
  AND token = 'rUrEBUGvqfWPyspzKpofwA52ls9oVdIc+UOKQnwohVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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