SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4d9a73e2f10fd34df57091e63650609a00b6455667ffb14d5c49b687e8e2232' 
  AND token = 'oMzJCzRUVjaBLF4zRqyzwVAnYq+9s7dcDZX2nDJCp6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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