SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd68157a13f567005e64d2a0b17b8208be0c9ef83d7322c0f455244396e9dd57f' 
  AND token = 'bOHBN9r9jJgzeqJlBNl4q6G4SKamZUz6qQZ12HN9M9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}