SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4de70dcd98d2333be60666c197548b83e375cebfd2e1b000d89b569149b475a0' 
  AND token = 'rGV7BvuzkFeHXxqbWvcLtmNy5hjllY4UUKGkXLwwIAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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