SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcd342cce6b6d01e6587095481d31e27376e34394431beba482f930c17b54db2' 
  AND token = '6077RdqpHs3/QGYgLr8p17HK4mpHa50xE2LQsWYR4KM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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