SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '386ccf25ef0c5e341fb9754a7665c8230d5021c02eb6d62358b094061c01c2ce' 
  AND token = 'jYwwxwzI7GgfU/YhR0YZ7RptLAR7AwFxBNCFYiYDt/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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