SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a6c4d2bfb93b9dd5b2d0448fc2b1a1064a7632cc05be03148a2aadcb0fa0bd1' 
  AND token = 'iLQgpYYclkh7xyaUujw/aR+Al060EP0zEAmneD68VkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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