SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8707d92029c05ec0a4718ad64af620e120b91d433a65ae380e5176b95983db58' 
  AND token = '+loVnzrN5PIk1/iZWrhoPJi5wzKmF+zBsrZP1kComk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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