SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '869ceda7ee1531ea26f696f00420865fa813c45081a2e5470ad7d4ac91a1da3a' 
  AND token = '9PTAE4SP1OUbOywIsQqqgLgApmteXSa5XLETOEPFlcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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