SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45309d840f9d6e8a19d567b6eee7a60cca40d7b8f1e8f1be4148f5d543c57549' 
  AND token = '+ew38Mo/esORzn1VT6gDhBxEE9zVOP+OBYNZsfakQx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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