SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a6336c5d3d25daa9b8232c6db1556bd137c9b8733d85698e605327876d7d274' 
  AND token = 'DFDTfA+kjIajp6ewlIj0UOyLFS3wf+jCfvmFf1ETFhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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