SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3685eaef4fe8e73cdd9a568377ce3675622067142e58377c41cc8b78a4c7b26f' 
  AND token = 'DLCXBoKe8OkaSkWUcoRZd7lHI+ie6XCQw613w2A2q9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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