SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3ed9b061c1245c2a4af8866296481f299b3850456f8cd9e9d5bbb93b2f9af68' 
  AND token = 'lOYvRAln4yzfDkhpApTEMMF8zE2qn5+mItAVmUQIaBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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