SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a20301f1337ef34674a26413c867a425d56b13f6b4b8c524959ad84a9420b6e' 
  AND token = '074KgDsNe3FZ7m+Z5vVXzMR7L8MJ9IPz33EXGAJbg6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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