SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9c11280ebcf0c21c64b0cbbb6ae2e71120fb3dd9ef4eab939148f81be4f9d96' 
  AND token = 'UH+FIgCJFhaV8aQsi5br8EnUoA5hSgbPOjJRUyTHBlI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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