SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feec2b100b1054b618334417b6b84c1517d62689e3bfe08d5950dc8a230c3411' 
  AND token = 'REby6nRxVYj/vvIw8OEi6VCSE0wStrdByGcalYmrDUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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