SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88dad84e95333723dd0d4c072bd45837f048abca85730f2ef1527bcd97ee2123' 
  AND token = 'TqtYuLb+coKjjQntNyI2qiKBqUvQlv5HPHjwnP3UY3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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