SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87811ff322a666ef97d1b072cdcba85512dfa6f46213ca1b1ffa8293c4d2ee8b' 
  AND token = 'yqQ5qhUocykGYArLzPbLx9GgJLSZ/+cXLIT8TCMJ30o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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