SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd908bb51c81ce43864592328dd431af44edfc7e36817a7321996de845c2923d7' 
  AND token = 'BzO5+xZi5gtvauyTVYBOlRQIwjDBaEOZ1M5JjX1+ak8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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