SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9228416951830e266d30ace40b18e9908330f7c525ea77f3c7e435953975ab' 
  AND token = 'vrlLTnVyQq9HUqMZevBE8BJLPrqVmV3PyuKxutzXLxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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