SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9e0442c3c9bc5395a49dc4f342a624d25f88ebe3626a7be6529d9d306a47731' 
  AND token = '8Y9KouCEb/GqR0+YFOzdpe08JH8RF35APzG6N/oE2gQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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