SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85c8b9577346c9a29bf7d4bbb22fc15fbcce569725fa0babd7a10498732cecfc' 
  AND token = 'dTzZUe1KIedQSpaqZ6hg/L2CMjtmP/nImT2MX8urivU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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