SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '686a5f66ab06c271b3c5de11c2a228cf95ba6db5bc7e5adf052a495c846caf39' 
  AND token = 'eLBW4uPzPwvsx1MAwgo53KtHvfwRzm3/SPs0MC2HBXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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