SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42b7109c8f092d9451d87f3a534ba1cbf4ca3fabb0205b9b8f15adec6635e8a0' 
  AND token = 'NJuPhD3gqzjFjedS0+JVHWiULrJ9eSUEvD7RRGGUDwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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