SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c952e429e8cd7ce6f0985f8b17cf2334c4d510e27c2a482c7dff2f07a448f410' 
  AND token = 'VOYuij1tl0/KMf8XwWlD0ez1NAk1pFnfG+jGa3mTJDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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