SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7b503fa91b773ae6885b9bc96aa11568d345b4ac6041e2fbed6c6e43f95ebd9a' 
  AND token = 'QN8I19NzWYFyvUzJalLXYl2TatO1IZ3Zgoo5+vZ0YNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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