SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6b27db86cf50156e799361e05bdec8adea11297d420941e7acefd33f112022a' 
  AND token = '98g2ohjCHDikq64RWYhOv/pKVUyvXXjD2bFrBAStdsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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