SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2b9fff43cb85f5ee4047d8ea5915280d16fd78021432adc20a54489b30cfb1d' 
  AND token = 'q0rVxTERO60u4TjN0GKpb0/MSI9aSg4ZLL8hWM+sUoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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