SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83cd4b74f5de86352fec2e0045293769e0762c6241991a7d9ed4d8cf4613cde8' 
  AND token = 'bqxnaZxyTgc7EIKUkmxwivKIUfY/9NZjFsKJf6yyVhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00578

JSON explain

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