Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '421f0421a85564f9f708a01b38381942b86b7f5ea4ebb9c8cc01ba0e39a2ca1d' 
  AND token = '6bpqQ3KLX1vDcktQTXi3k2pFY+VLQ2zmuHdQiKPB+x4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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