SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cccfffa4f4bdf074085318db0a53e4b2bcd371711c666f2498707dcd9c981c2' 
  AND token = 'Nnuie6tBFQkfS+OnCvz30tEEmdxlMGkDut7oBuX2ZmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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