SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8d9fcc3873063f185b0e9031098a3fe93b28f8af1cd4550ac4b9ac584220a9e' 
  AND token = 'HkBiqPvObuPZYAxtgsieJ4aPM0o3HrR6Ky/1xk72ibY=' 
  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"
    }
  }
}