SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab665f0c0751cab146729f9ae8879244254113bca2ae48f6a1e55f461e03fba' 
  AND token = 'Zr2wmMG330TtxwD3kPi8TmTmPbS5XhggAYIipOB5QcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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