SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23be2850a03a81a2e1eed5abfd97a7dedced19c30b33803799c10e8e982e9eb3' 
  AND token = 'fX/DfNOKqdKQQo0kWN5udUZXYpoguHAnGCJKs6UFKLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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