SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cc27beb17f06cfe8351888f0f464e140aee8d971fabd7a2eee8ef2ecb19c117' 
  AND token = 'A5BRlAtvAyBxO0YmHLKpxGR224MSt1vaJ5IyNzYNHX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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