SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1852bdfeb46135aabed13104e59e70e4c04f9f82477846f2af84b6c25b569b8' 
  AND token = 'UVF442rPokmXADUah1UMpjZFNdKSs8eIkIakF9JJ/nw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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